A sex position involving shoving your thumb into certain holes. Named after youtuber Kentucky Ballistics after shoving his thumb into his neck after his 50 cal exploded
Refers to Scott from Kentucky Ballistic's near fatal injury from a .50 BMG explosion that was averted when he put his thumb into a hole in his neck to stop the bleeding.
When you're nailing your sister from behind and you slip in the back "accidentally" so you shove your thumb in her asshole so blood doesn't get on your bed.